With the recent prevalence and development of network technologies, a switch device capable performing higher communication, and flexibly compatible to new protocols, etc., has been desired.
Such a switch may be an openflow network, etc., described in, for example, Dr. Marcus Brunner, “Programmable Flow-based Networking with OpenFlow” (http://docbox.etsi.org/Workshop/2010/201003_FNTWORKSHOP/7_ARCHITECTURE/BRUNNER_OpenFlow.pdf, hereinbelow, referred to as Non-Patent Document 1).
FIG. 11 illustrates an outline of the openflow network. The network shown in this example comprises a switch 10′, a control device 30′, and a plurality of terminal apparatuses 40′. The switch 10′ has a plurality of network ports, and each of the terminal apparatuses 40′ is connected to any one of the network ports of the switch 10′. The switch 10′ and the control device 30′ are connected to each other via a network (Internet, etc.) so as to be mutually communicable.
When the terminal apparatus 40′ is activated, the terminal apparatus 40′ starts data transmission to the switch 10′. The data is divided into frames, and the first frame (the first frame received from the terminal apparatus 40′) is transmitted by the switch 10′ to the control device 30′. Here, communication between the switch 10′ and the control device 30′ are encrypted by SSL, etc.
Upon receiving the frame from the switch 10′, the control device 30′ judges, in accordance with a predetermined judgment criterion, whether or not a new process is necessary relating to the communication with the terminal apparatus 40′ which has transmitted the frame. When judging that a new process is necessary, in accordance with the judgment, the control device 30′ transmits the information defining the content of the necessary process to the switch 10′. The switch 10′ receives and stores the information, and subsequently, executes the process defined by the information.
The content of the process defined by this information includes a rule and an action. Here, the rule refers to information representing what the object is, and the action refers to a specific content of a process relating to the object. As an example, when a content of a process is defined, and in the content, the rule is a specific port number, and the action is multicast, the switch 10′ operating in accordance with this definition, performs multicast of the data which has been received from the terminal apparatus 40′ through a port having the specific port number, through another port.
According to this example, in accordance with a condition predetermined by a user (for example, communication using a specific protocol), if the first frame transmitted/received between the terminal apparatus 40′ and the switch 10′ satisfies this condition, and the judgment reveals the start of communication requiring a new process (for example, judgment reveals the start of communication using the specific protocol), the control device 30′ transmits information defining the new process (information defining a process relating to the above specific protocol, etc.), and subsequently, the switch 10′ performs the process on the basis of the information, and becomes compatible with the new protocol.